Question

A sample of an oxide of antimony (Sb) contained 51.5 g of antimony combined with 16.9 g of oxygen. What is the simplest formula for the oxide?

Answer 1

You need to know the molar ratio for Antimony Oxide! Since Sb has an oxidation of +3 and Oxygen has a oxidation of -2, you need two Sb atoms and three O atoms.

Sb2O3

Figure out how many moles you have of antimony and oxygen..

51.5 g Sb * 1 mol/ 121.76 g= 0.43 moles Sb

16.9 g O * 1 mol/ 16 g= 1.06 moles O

I don't think even in the simplest form, the masses of the elements given are sufficient for a stable compound of Sb2O3.

Answer 2

51.5 g of Sb*(1 mole/121.76 g)= moles of Sb=0.418

16.9 g of O * (1 mole/16.0 g)= moles of O=1.06

divide lowest moles by the other


Sb=0.418/0.418=1

O=1.06/0.418=2.52

2.52 *2 to get a whole number

Sb2O5

Answer 3

I could be wrong though.

Answer 4

Thank you Mr. Devron! I learnt something from you as well. The compound is Antimony Pentoxide, and I did indeed not realize that after dividing by the lowest moles you can multiply!

Answer 5

hey i got Sb2O5

for the oxide is O5 right?

Answer 6

Sb2O5 is correct. As for multiplying by whole numbers; remember that you can round to whole numbers as long as you don't round too much. That is, 8.1 can usually and safely be rounded to 8.0 or 8.9 to 9.0 but rounding 2.5 to 3 or 2 isn't done for 2.5 can be multiplied by whole numbers to get a whole number. Numbers like 2.25, 2.33, 2.5, 2.67, 2.75 usually aren't rounded but multiplied by whole numbers to obtain whole numbers; i.e., 2.33 x 3 = 6.99 which then rounds to 7.0